XBee‐PRO®900HP/XBee‐PRO®XSCRFModules
©2014DigiInternationalInc. 108
application does not allow control over when data is received, except by waiting for dead time between bursts
of communication.
If the command is sent in the middle of a stream of payload data to be transmitted, the command will
essentially be executed in the order it is received. If the radio is continuously receiving data, the radio will wait
for a break in the received data before executing the command. The CTS
signal will frame the response
coming from the binary command request [Figure ].
A minimum time delay of 100 µs (after the stop bit of the command byte has been sent) must be observed
before pin 5 can be de-asserted. The command executes after all parameters associated with the command
have been sent. If all parameters are not received within 0.5 seconds, the module aborts the command and
returns to Idle Mode.
Note: Binary commands that return only one parameter byte must also be written with two parameter
bytes, 0-padded, LSB first. Refer to “Programming Examples” section [p18] for a binary programming
example.
Commands can be queried for their current value by sending the command logically ORed (bit-wise) with the
value 0x80 (hexadecimal) with CMD asserted. When the binary value is sent (with no parameters), the current
value of the command parameter is sent back through the DO pin.
BinaryCommandWritethenRead
Signal#4isCMD(pin16)
Signal#1istheDIN(pin3)signal
totheradio
Signal#2istheDOUT(pin2)signal
fromtheradio
Signal#3isCTS
(pin12)
In this graph, a value was written to a register and
then read out to verify it. While not in the middle of
other received data, note that the CTS
signal outlines
the data response out of the module.
IMPORTANT: For the XBee module to recog-
nize a binary command, the RT (DI2 Configuration) parameter must be set to one. If binary program-
ming is not enabled RT = 0 or 2, the module will not recognize that the CMD pin is asserted and
therefore will not recognize the data as binary commands.
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